import pymysql# 封住数据库工具类
class DBUtil(object):# 添加属性conn = None@classmethoddef __get_conn(cls):if cls.conn is None:cls.conn=pymysql.connect(host="123.45.23.2",port=1232,user='admin',password="123456",database='test_db',charset='utf-8')# 返回 非空连接return cls.conn@classmethoddef __close_conn(cls):# 判断: conn 不为空,需要关闭if cls.conn is not None:cls.conn.close()cls.conn=None# 常用的方法 查询@classmethoddef select_one(cls,sql):cursor=Nonetry:# 获取连接cls.conn = cls.__get_conn()# 获取游标cursor = cls.conn.cursor()# 执行sqlcursor.execute(sql)# 提取第一条数据res = cursor.fetchone()